In the state of the art of rotor spinning machines, it has long been customary to drive all of the work elements of the work stations centrally, in order to be able to operate the machines cost-effectively. In each case, the drive of the identical work elements is effected by a central drive arranged on one end of the rotor spinning machine, which drives the work elements of all work stations by means of a shaft over the length of the machine or a tangential belt. A device for producing the negative spinning pressure required for yarn production is arranged centrally in a frame at one end of the rotor spinning machine. The negative spinning pressure is distributed from there to all work stations through a negative pressure channel over the length of the machine. Usually, the central drives for the work elements are accommodated in a first end frame of the rotor spinning machine and the device for producing the negative spinning pressure is accommodated in a second frame at the opposite end of the rotor spinning machine.
In order to meet the requirements for an increase in productivity, it was necessary to increase the number of work stations on a rotor spinning machine. However, due to problems caused by elongation and torsion, the described machine concept reaches its limits with a work station that is driven centrally from a machine end. The same applies to the supply of the work stations with negative spinning pressure. As such, various machine concepts that enable an increase in the number of work stations per spinning machine have already been proposed.
Therefore, DE 10 2004 016 796 B4 proposes dividing a rotor spinning machine into two sections and arranging central drives not only in an end-side frame, but also in an intermediate frame arranged between the two sections. Here, the work elements of the first section are driven by a central drive arranged in the end-side frame and the work elements of the second section are driven by a central drive arranged in the intermediate frame. Furthermore, the two sections of the rotor spinning machine are to be separately supplied with negative pressure via two separate lines. The negative pressure source required for this purpose can be arranged in one of the end-side frames or in the intermediate frame.
Moreover, DE 10 2006 029 056 A1 describes a rotor spinning machine with an intermediate frame arranged between the work stations. At the same time, at least the central drive for the thread traversing devices and the device for producing the negative spinning pressure are to be arranged in the intermediate frame. Thereby, both the required length of the thread guide rods along with the required length of the negative pressure channels for the distribution of the negative spinning pressure to the work stations are reduced, since they have to extend only from the intermediate frame to one of the two machine ends.
By means of such an intermediate frame, it is possible to reduce the length of central devices, and to thereby reduce the technical problems caused by elongation and torsion in long machines. However, the accessibility to the components arranged in the intermediate frame, along with the supply and disposal on the machine, can be made more difficult by this arrangement. However, in addition to mastering the technical problems with long machines, it is likewise necessary to be able to operate them in a cost-effective and energy-saving manner.